I just noticed something interesting.
The Hide in Plain Sight ability of a shadowdancer does not work the same as that of a level 17 ranger.
The ranger requires being in a favored terrain (or any natural terrain in 3.5) and the shadowdancer needs to be near dim light.
Additionally the shadowdancer's ability adds the following:
Going back to the original question though... You'd need the feat Spring Attack, otherwise you'd only be hidden every other turn and would suffer an attack of opportunity every time you went to hide. Additionally since the enemy knows you're out there somewhere and is probably looking in your direction when you come out of hiding, I'm not even sure if they'd be flat-footed.
The Hide in Plain Sight ability of a shadowdancer does not work the same as that of a level 17 ranger.
The ranger requires being in a favored terrain (or any natural terrain in 3.5) and the shadowdancer needs to be near dim light.
Additionally the shadowdancer's ability adds the following:
This sentence is absent in the ranger's ability. This means that darkvision would work against a ranger but not against a shadowdancer.A shadowdancer can hide herself from view in the open without anything to actually hide behind.
Going back to the original question though... You'd need the feat Spring Attack, otherwise you'd only be hidden every other turn and would suffer an attack of opportunity every time you went to hide. Additionally since the enemy knows you're out there somewhere and is probably looking in your direction when you come out of hiding, I'm not even sure if they'd be flat-footed.